H 264 MPEG4 Part 10 Nimrod Peleg March

Encoder + . . image sequence + DCT Q - Q-1 Intra / Inter

H. 264 Brief review • Goal – Develop a high-performance video coding standard. •

H. 264 Encoder Coding control + + IDCT Q . . Image sequence IDCT

Transform • DCT like. • Integer arithmetic only. – without multiplications. • Optional use

Quantization • Compounding quantization step. • Thirty-two different quantization step sizes. – The step

Frames Store • The H. 264 standard offers the option of having multiple reference

Motion Estimation & Compensation • Motion Estimation is where H. 264 makes most of

Motion Estimation & Compensation • Seven optional modes. Different modes of dividing a macroblock

Entropy Coding • H. 264 has adopted two approaches for entropy coding : –

Intra prediction • 9 optional prediction modes for each 4 x 4 luma block.

Summery • Transform – IDCT – Optional use of a 4 x 4 transform

Summery • Frames store – Multiple reference frames may be used for prediction. •

Slides: 18

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H. 264 / MPEG-4 Part 10 Nimrod Peleg March 2003

Encoder + . . image sequence + DCT Q - Q-1 Intra / Inter switch DCT-1 + M. C. M. E. VLC + + MEM 0101. . . bit stream

Previous Standards

H. 264 Brief review • Goal – Develop a high-performance video coding standard. • Start from zero. • No backward compatibility. • Assumptions – Block based. – Software implementation. – Network friendly.

H. 264 Encoder Coding control + + IDCT Q . . Image sequence IDCT + M. E. 0101. . . bit stream Q -1 Intra/Inter Switch M. C. Entropy Coder -1 + + Frames Store

Transform • DCT like. • Integer arithmetic only. – without multiplications. • Optional use of a 4 x 4 transform block size.

Quantization • Compounding quantization step. • Thirty-two different quantization step sizes. – The step sizes are increased at a compounding rate of approximately 12. 5%. • Different quantizer for luminance, chrominance. • Two different coefficient-scanning patterns. – The simple zigzag scan. – The double scan.

Frames Store • The H. 264 standard offers the option of having multiple reference frames in inter picture coding. • Up to five different reference frames could be selected. – Resulting in better subjective video quality and more efficient coding of the video frame under consideration. • Using multiple reference frames might help making the H. 264 bit-stream error resilient.

Motion Estimation & Compensation • Motion Estimation is where H. 264 makes most of its gains in coding efficiency. • Quarter pixel accurate motion compensation. • Translation only. • The standard does not determine which algorithm should be used.

Motion Estimation & Compensation • Seven optional modes. Different modes of dividing a macroblock for motion estimation in H. 264

Entropy Coding • H. 264 has adopted two approaches for entropy coding : – Universal Variable Length Codes (UVLCs) • One table. – Context-Based Adaptive Binary Arithmetic Coding (CABAC)

Intra prediction • 9 optional prediction modes for each 4 x 4 luma block. • 4 optional modes for a 16 x 16 luma block. • 4 optional prediction modes for a 8 x 8 chroma component. • One mode for 4 x 4 chroma block.

Summery • Transform – IDCT – Optional use of a 4 x 4 transform block size. • Quantizer – step sizes are increased at a compounding rate of approximately 12. 5%. – Two coefficient-scanning patterns. • Motion estimation and compensation – Translation only. – A number of different block sizes are used for motion prediction. – Quarter pixel positions are used for motion prediction.

Summery • Frames store – Multiple reference frames may be used for prediction. • Entropy coding – Only one regular VLC is used for symbol coding.